Process of forming and repairing the linings of furnaces.



A. SGHWARZ.

PROCESS OF FORMING AND REPAIRING THE LININGS 0F FURNACES.

- APPLICATION FILED MARS, 1913.

Patented Jan. 19, 1915.

l/VI/ENTOR WITNESSES.

TTOR/VEVS A l I v v UNITED STATES PATENT OFFICE.

ALFRED SCHWARZ, 0R NEW YORK, N. Y., ASSIGNOR TO NEW YORK CEMENT GUN COMPANY, 015 NEW YORK, N. Y., A CORPORATION OF NEW YORK.

PROCESS OF FORMING AND RE I PAIRING THE LININ'GS OF FURNACES.

Specification of Letters Eatent.

Patented Jan. 19, 1915.

Application filed March 3, 1913. Serial No. 751,808..

To all whom it may concern;-

Be it known that I, ALFRED SCHWARZ, a subject of the Emperor of Germany, 'residing at New York, in the county and State of New York, have invented certain new and useful Improvements in Processes of Forming and Repairing the Linings of Furnaces, of which the following is a full, clear, and exact description.

Furnaces which are subject to relatively high temperature, such as those for melting, smelting or refining .metals, the manufacture of glass or the like, or those heated by electricity, or furnaces for boilers and the like, have heretofore been constructed with linings composed of fire-brick aggregates of silica or magnesite sand and the like, ee-

mented together by binders such for example, as fire-clay or hydro-carbons such as coal tar and similar substances. ihe fusion point of the fire-clays thus used as a binder is very much lower than that of the refractory substances constituting the body of the lining, and its presence reduces the value of the refractory material in direct proportion to the quantity employed, as it renders the furnace and its lining subject to the disintegrating action of high temperature and a consequent gradual deterioration of the same. Repairs of such furnaces, effected by the use of refractory substances composed of mixtures of refractory sands with a binding material such as fireclay, and water, are for the same reasons subject to similar deterioration. These difficulties are not obviated by the use of hydro-carbons as binders since the latter contain a large proportion of volatile constituents which, being driven ofi by heat, leave the lining in a more or less porous condition as only a comparatively small amount of solid carbon remains. It is well known,

moreover, that a high degree of density in the lining is desirable in order that the contents of the furnace, such as molten metals, may not find their way into the body of the lining, since such substances will result in a deterioration of the lining which is in direct proportion to the square of the surface exposed to the corrosive action of the molten charge. Naturally, in the case of a porous lining the surface thus exposed is much greater than in a homogeneous mass. In the construction of furnaces, therefore, it becomes of primary importance, in order to produce a homogeneous or uniformly refractory lining of great density, to eliminate such binders as have heretofore been employed, or to minimize their quantity to such extent that their presence will not majecting the aggregates of which the bricks are composed, to hydraulic or other pressure in molds, but in the production or repair of furnace linings such rocesses are not available, while the use of substantial proportions of binding material in building up a lining of bricks or shapes of refractory material is essential. however, that a homogeneous lining of the requisite density may be produced by applying to the form or wall of a furnace, comminuted refractory material at high velocity continuously or successively in relatively small quantities, and at the same time subjecting said material as it is thus applied to fusing temperature, thus furnishing successive thin layers of refractory material in heated and softened state into which the refractory material which follows is embedded, and building up a lining homogeneous and vitrified throughout. If

. the entire lining were built up of the ultimate thickness required, before the fusing heat was applied, only the outer or exposed portions of the lining would be fused, leaving the under portions merely dried out and porous, and the non-homogeneous lining thus produced would crack and fall oil, But by subjecting the comminuted material to fusing temperature as it is ap-' plied to the furnace form or wall, a refractory lining is produced which is vitreous, dense, and homogeneous throughout, thus producing efi'ects, so far as density is con corned, like those of high pressures, and obviating entirely, or reducing to a minimum, the use of binders or adhesive agents such as would impair the heat resisting qualities of the finished structure.

I have discovered,

In carrying out my invention, I may use vcompressed air as the propelling agent, and I can drive finely comminuted refractory capable ofblowing the sand or fine particles material into crevices between bricks or of material against the surface to be operblocks of refractory material and cause it to .ated upon at velocities from'eight to fifteen adhere to the latter either in such crevices thousand feet per minute, but I may use or on exposed surfaces, whether on the side lower velocities, good results being obwalls or roof of a furnace, and whether the tained with any velocity of projection in exsame be hot or cold.

cess of three thousand feet per minute. Any In the accompanying drawings, to which known and suitable means for producing the I shall now refer for a better understanding requisite high temperature of the commiof my invention: Figure 1 shows a device or nuted material as it is thus applied may be apparatus for projecting the comminuted reemployed. I prefer to use for this purpose fractory material forcibly against the wall a high power flame near the nozzle of the of the furnace in accordance with my inveninjector which will instantly raise the temtion, a furnace being also shown in horizonperature to fusing temperature at the point tal section in order to illustrate the manner of application; In this way I may fuse reof using the apparatus. Fig. 2 is a view of fractories directly onto the walls, roofs and the nozzle of the apparatus of Fig. 1, assobottoms of furnaces under higher tempera mated with a torch as the agent for maintures than those at which such furnaces are taining the requisite softening or fusing normally. operated. Since the term retemperature at the point of application of fractoryv is only relative, and as all materials used in furnace construction are fusible, it will be understood that a furnace might be lined with material fusible at three gun so called, and the torch, are at the thousand degrees which is'fully capable of present time well known and in use for form or wall of the furnace.

resisting if the furnace is normally operated other purposes,' and as they, in themselves,

' flame which will instantly raise the temper at two thousand degrees. In such cases I form no part of my present invention, they project the refractory material a ainst the re Shown conventionally in forms which furnace walls of the preferably hot rnace, adapt them to carry out my. process.

using near the injector nozzle a high wer The implement shown in Fig. 1 comprises a nozzle A into which opens, in well known ture at the point of application, and par- Ways, a pipe or tube B leading from an air tially fuse the furnace wall, so that the re-' reservoir (3 in which air is compressed and fractory particles projected from the injecstored by a suitable pump D, and a pipe E tor nozzle against the wall will imbed themconveying in a finely divided state a Suitselves in the partially fused surface'of the a le refractory material from a hopper or same, and, in their turn, become softened other feed device F. In case at any time it by the high power flame so that the follow be desired to add a liquid to the comminuted. ing particles will imbed themselves therein, refractory material, before it is discharged and so on. On withdrawing the flame, the from the nozzle, a tube or pipe G is promaterial congeals sufliciently to Withstand vided leading from a suitable source of the normal lower temperature of the furliquid supply, which is not shown. The nace. I have found incases where, for inpipes for any desired distance back of the stance, silica sand is used which is practinozzle are rigid, so that the latter may be cally free from lime and other fluxes, that directed either from within or without the minute quantities of flux maybe advanta-' furnace to any portion of the walls thereof geously used, as it facilitates the partial by the operator, and when in use a suflifusion of the lining, and in such cases I may ciently powerful air pressure is used to takeuse a weak solution of calcium chlorid, or up the refractory material and project it borax or the like. from the nozzle violently or at high velocity Under my invention, the lining may be upon the adjacent form or, wall of the furapplied while the furnace is under construcnace. The requisite high softening or fustion, or while it is cooled off so that it is ing heat at the point where the refractory possible to enter the same. On the other material is applied to the furnace form or hand, as hereinbefore indicated, the lining wall may be produced and maintained in may be applied or repaired while the furany suitable way and by the employement nace is heated to a degree too high to perof any suitable known instrumentalities. I mit entrance to it. In the latter case, I prefer for this purpose the means illustrated employ nozzles which are of such length as in Fig. 2, comprising a torch H attached to to permit the operator to stand outside the the nozzle A in any convenient manner, and furnace and to reach it at any desiredpoint supplied through tubes K and L with acetyin its interior. lene and oxygen, or'other ases capable of My process obviously is applicable not maintaining a persistent flame of intense only to the forming, but also to the repair-- heat, which, in the use of the device, is di- The devices in question, viz: the .cement the comminuted refractory material to the ing, of furnace linings. By the same process rected against the furnace wall within or uo near the area, upon which the. jetor refrac-- tory material impinges. These or other destate -at high velocity against" the fo'ri'n" or wall of a furnace and subjecting said wall to fusing temperature at the time and at the point of application only of said ma- 15 terial.

In testimony whereof I aflix my signature in the presence of two subscribing witnesses.

ALFRED SCHWARZ. Witnesses:

PHILIP S. HJLL, THOMAS J. BYRNE. 

